Assistive Zoom is a small interface tweak that enables a one-finger zoom gesture by placing a small slider button at the side of the screen. This allows you to use pinch-to-zoom on supported apps, pages and documents, even when using only one hand. It's an especially useful tweak for users on the go with a phone or phablet they can't always manipulate with two hands. A Pro version ($0.99) removes ads and allows for further customization.